Wax compositions



Patented Dec. 4, 1 951 Rahway, N. J., as

velopment Company,

signors to Standard Oil Deair-corporation of Delaware No Drawingi: App! anon October. 11, 1949, serialiNiy. 1.20;812-

6 Claims.

The present invention relatesto wax composit'i'ons which are suitable for'high' temperaturquse aniparticularly to waxes, which remain stable 't'o'heat' over extendedfperiods of'time. 7

Several typesof' waxes maybe. derived: from petroleum oils and in order that. no confusion will. arise with respectto the typesofwaxes employed in this. invention,,a brief'description will Y.

be given of" the method. for preparing the;waxes used in the present invention.

The term paraffin hard, crystalline wax commonly obtained from petroleum distillatesderivedfrom mineraloil's of the mixed base orparaffin base type. By the present refining methods, the crude oil is subjected to distillation whereby; it. is separated into a series of fractions known, as paraffin distill wax is usedltod'eiine the latesr The'wax isseparatedifromthejparaffin distillate by chilling and filteringorby the use of a solvent'as, forexamplepropaneor a ketone, such as methyl ethyl keton.e The wax obtained by-either of these methods stillcontainslfrom 10 to 50% oil and is generally referred to as"slack wax. This slack wax is subjected to a sweating operation to remove the oil. The resulting wax usually contains 3 to 6% oil but by proper sweating the oil may be as low as l to 3%. This wax known as crude scale wax is again sweated to reduce the oil content to less than 0.5% and even as low as 0.05%. This product is known as refined wax or "parafiin wax and is graded according to tensile strength, melting point, oil content, hardness, etc.

It has been suggested in the prior art that for some purposes it is advantageous to add certain metal salts, particularly the metal salts of organic fatty acids to parafiin waxes. Various investigators have found that the addition of metal salts of the character referred to have utility for improving the tensile strength and melting point of the wax. There appear to be several theories as to the operation of such metal salts in conjunction with the soaps. One such theory is that the addition of salts of low molecular weight acids to soaps of relatively high molecular weight results in the formation of a complex with superior grease thickening effect and of improved stability.

Suggestions in the prior art have included the use of the salts of saturated fatty acids, such as stearic and oleic acids. However, these salts are difficult to solvate, temperatures of about 400 F.

being required.

According to the present invention, the salts of entirely different. purposes.

certain acids, particularly the salts of heterocyclic acids, such as vfuroic acid, are highly "useful as ingredients'of waxes, Furoic acid, for exam? ple, may be readily derived from furfural which is abundantly available at low prices at this time. Thiofuroic acid may be'used. Othenrel'ated compositions appear. also, to be similarly'useful', for

example, alkyl-furoic acid, thiophene carboxylic acid, etc. These compounds all have fivemembered furan-type-rings-andare of low molecular weight.

1 The use of'the salts of acids of the type set forth above, such as furoio acidg is not to be confused'ysithv the use of. related esters which have Thus; ithas been suggested in the prior: art, Zimmer etai. Batent No. 2,1-l-3 J5e, dated April 12; 1938, that certain furoie acid. esters. are useful as oiliness agents, in various lubricating, compositions. This reference suggests, that. such esters. may be used either in lubricating oil or lubricating greases. The esters, howeven are entirely different from the salts employedin' the present instance andtheir function is not related in any way to the function of the furoic acid salts and the equivalent compositions of low molecular weight heterocyclic acids.

U. S. Patent No. 2,388,166 recites the use of lithium stearate and other lithium salts of monoor polybasic aliphatic carboxylic acids containing at least eight carbon atoms to increase the melting point of the wax. However, these materials as shown below do not have the beneficial properties of the addition agents of the present invention.

In the present case, the low molecular weight salts are added to the wax for the purpose, as indicated above, of improving high temperature stability of the Wax and also to increase its tensile strength.

In general, the metallic element of the salts may be any of the alkali or alkaline earth metals. Sodium and lithium are preferred of the alkali metals and calcium is the preferred alkaline earth metal partly because of its low cost. Salts of potassium, strontium, magnesium and barium may be used, however, as well as the soaps of any of these metals and mixtures of salts and/or 2,577,643 3 composition of the present invention containing lithium salt of furoic acid in comparison .with a wax containing lithium stearate:

4 refined paraflin wax combined with 1 to 5% of an alkali metal salt of a heterocyclic carboxylic acid, said heterocyclic acid being a low molecular TABLE Lithium salts in paramn wax A 50 gram sample of each sample was placed in a Pyrex beaker, covered with a watch glass and held at 70 C. for eleven days in a circulating air oven and the samples tested for odor daily. At the end of the test the samples were evaluated for taste as well as for odor.

ExcellentNo taste and odor. Good-An odor but not objectionable; no taste. FairS1ightly objectionable odor and taste.

Poor-Objectionable odor and taste.

The above data indicate that the tensile strength of the Wax composition containing lithium salt of furoic acid is equally as good as that of a wax containing lithium stearate while the heat stability is remarkably increased.

In the data given above, the lithium salt of furoic acid was used as the addition agent, although the invention can be carried out with other alkali and alkaline earth salts.

The nature of the present invention having been fully set forth and specific examples of the same given, what is claimed as new and useful and desired to be secured by Letters Patent is:

1. A wax composition consisting essentially of refined paraifin wax and 1 to 5% of a metal salt chosen from the class consisting of alkali metal and alkali earth salts of a, heterocyclic carboxylic acid, said heterocyclic acid being a low molecular weight acid having a five-membered furan-type ring.

2. A wax composition consisting essentially of The results were labeled according to the following schedule:

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,284,065 Myers May 26, 1942 

1. A WAX COMPOSITION CONSISTING ESSENTIALLY OF REFINED PARAFFIN WAX AND 1 TO 5% OF A METAL SALT CHOSEN FROM THE CLASS CONSISTINGOF ALKALI METAL AND ALKALI EARTH SALTS OF A HETEROCYCLIC CARBOXYLIC ACID, SAID HETEROCYCLIC ACID BEING A LOW MOLECULAR WEIGHT ACID HAVING A FIVE-MEMBERED FURAN-TYPE RING. 